Natural enemy enhancement and botanical insecticide source: a review of dual use companion plants

Applied Entomology and Zoology https://doi.org/10.1007/s13355-018-00602-0 REVIEW Natural enemy enhancement and botanical insecticide source: a review of dual use companion plants Blankson W. Amoabeng1,2 · Annie C. Johnson1,3 · Geoff M. Gurr1,3,4 Received: 6 November 2018 / Accepted: 20 December 2018 © The Author(s) 2019 Abstract Intensive agriculture, which is associated with heavy inputs of synthetic insecticides, has serious ecological impacts, leading to loss of vital ecosystem services including insect-mediated pest suppression. In recent years, efforts have been made towards obtaining safer options to chemical insecticides for sustainable pest management. Habitat manipulation is a part of conservation biological control which aims at providing floral resources, alternative prey and shelter to predators and parasitoids to enhance and sustain natural pest suppression. The use of plant extracts as botanical insecticides is also an important provisioning ecosystem service. Selection of plant species for habitat manipulation has focused mainly on plants with suitable floral qualities to support natural enemies. To increase the benefits, habitat manipulation plants that can provide multiple ecosystem services in addition to floral resources would be an ideal. In this review, we focus on the potential of achieving the dual ecosystem services of bioinsecticidal source plants in addition to the provision of floral resources from selected plant species. Our literature search found 283 plants species from 44 plant families that have been involved in habitat manipulation studies. Fifteen of these plant families have species that have been exploited for their insecticidal properties. Three families, Apiaceae, Asteraceae and Lamiaceae, have the largest number of species that have been used for both habitat manipulation and botanical insecticides. Of the four most popular habitat manipulation plants, alyssum Lobularia maritime (L.) Desv. (Brassicaceae), buck wheat Fagopyrum esculentum Moench (Polygonaceae), coriander Coriandrum sativum L. (Apiaceae) and phacelia Phacelia tanacetifolia Benth. (Boraginaceae), buckwheat and coriander have been used for insecticidal purposes whilst no records exist of phacelia and alyssum as botanical insecticide species. There is great potential for identifying plant species that can support natural enemies as well as providing potent plant extracts as botanical insecticides by selecting species from the Apiaceae, Asteraceae and Lamiaceae families. Keywords Habitat manipulation · Conservation biological control · Biopesticides · Dual ecosystem services Introduction * Geoff M. Gurr 1 School of Agriculture and Wine Sciences, Charles Sturt University, Orange Campus, Orange, NSW, Australia 2 Council for Scientific and Industrial Research (CSIR), Crops Research Institute, Kumasi, Ghana 3 Graham Centre for Agricultural Innovation (New South Wales Department of Primary Industries and Charles Sturt University), Orange Campus, Orange, NSW, Australia 4 Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China Agriculture globally is facing many challenges including climate change, biodiversity loss and rising demands for food production (Deutsch et al. 2018; Rockstrom et al. 2009; Tilman et al. 2011). In response to these challenges, a growing volume of research is contributing towards a redesign of agricultural systems that provide nutritious food for all healthy and resilient ecosystems (Bommarco et al. 2013; Pretty et al. 2018; Struik and Kuyper 2017; Tilman et al. 2011). Evidence is growing that a sustainable intensification of agriculture can be achieved by combining scientific and farmer knowledge to develop ecologically and agronomically compatible practices (Pretty et al. 2018). Integrated pest management (IPM) is an example of redesigning intensive agricultural systems. Instead of 13 Vol.:(0123456789) Applied Entomology and Zoology relying principally on synthetic pesticides, IPM uses nonchemical or botanical insecticide measures to suppress pest population increase and a range of curative management tactics with synthetic pesticide use as last resort (Barzman et al. 2015). The declining availability of many pesticides due to resistance and deregistration, reflecting increasing awareness of their environmental and human health consequences, has driven changes towards ecologically based practices (Barzman et al. 2015; Borel 2017; Chagnon et al. 2015; Li et al. 2017; Sumon et al. 2018). A central part of IPM is biological control in which natural enemies including parasitoids, predators and pathogens are introduced and/or promoted (Bale et al. 2008; Gurr et al. 2000a, 2018). Conservation biological control focuses on natural enemies already present in an agroecosystem and aims to maximize their impact on target pests by, for example, reducing the adverse effects of insecticide use (Begg et al. 2017; Ehler 1998). Habitat manipulation works in conjunction with conservation biological control and is used to provide conditions that promote natural enemies and suppress pest populations (Fiedler et al. 2008; Gurr et al. 2000b, 2017). This can include field level interventions such as establishing plants to provide floral resources, refuges and alternate hosts for natural enemies (Griffiths et al. 2008; Gurr et al. 2017). Plants that are selected for habitat manipulation have usually been studied for morphological and physiological floral characteristics that provide optimum benefits to natural enemies (Baggen et al. 1999; Balzan et al. 2014). Habitat manipulation tactics can extend beyond the field to include landscape features including riparian areas and treelines, although the effect of landscape features on crop pests is variable (Karp et al. 2018; Tscharntke et al. 2007). Ecologically based pest management tactics such as conservation biological control have been shown to reduce the use of synthetic insecticides in a variety of cropping systems whilst maintaining or increasing crop yields and efforts are being made to up scale the practice globally (Pretty et al. 2018; Wyckhuys et al. 2013; Xu et al. 2017). Despite these advantages, however, uptake of conservation biological control on a wide scale is limited (Gurr et al. 2016). In cases where uptake has been strong, the vegetation used in habitat manipulation provides multiple ecosystem services rather than suppressing pests alone (Khan et al. 2006, 2012). To date, however, there is a major gap in knowledge about the possibility of habitat manipulation plants providing botanical insecticides. This is important because synthetic insecticides present significant risks to human health. Agricultural workers and consumers are at risk of being negatively affected by insecticide products, tank mixes, drift, residues and breakdown products, especially as a consequence of poor registration, storage and misuse (Eddleston et al. 2002). In agricultural are (...truncated)